Commonly assigned PCT Patent Publication No. WO 2005/030140, incorporated by reference herein in its entirety, discloses novel inhibitors of multiple receptor tyrosine kinases (RTKs) implicated in tumor growth and angiogenesis, pathologic bone remodeling, and metastatic progression of cancer. In particular, the compound N-{4-[(6,7-dimethoxyquinolin-4-yl)oxy]phenyl}-N′-(4-fluorophenyl) cyclopropane-1,1-dicarboxamide is specifically described in WO 2005/030140 as an RTK inhibitor. The chemical structure of N-{4-[(6,7-dimethoxyquinolin-4-yl)oxy]phenyl}-N′-(4-fluorophenyl) cyclopropane-1,1-dicarboxamide is represented by Compound 1.

Compound 1 was found to have an enzyme Ret IC50 value of about 5.2 nM (dihydrate) and an enzyme c-Met IC50 value of about 1.3 nM (dihydrate). The assay that was used to measure this c-Met activity is described in paragraph [0458] in WO2005/030140.
During initial development experiments, Compound 1 (a free base) was found to be a BCS class II compound having low solubility and high permeability. Because Compound 1 was observed to have low solubility in water, it was initially considered unsuitable for solid oral dosage development, and hence the pharmaceutical development focused on finding a salt with suitable hygroscopicity, thermal stability, chemical stability, physical stability, and solubility.
The malate salt of the Compound 1, as described in WO 2010/083414, the entire contents of which is incorporated by reference, was subsequently identified as providing an acceptable combination of crystallinity, solubility, and stability as compared to cabozantinib free base. On Nov. 29, 2012, the S-malate salt of N-{4-[(6,7-dimethoxyquinolin-4-yl)oxy]phenyl}-N′-(4-fluorophenyl) cyclopropane-1,1-dicarboxamide (also known as cabozantinib or COMETRIQ®) was approved by the United States Food and Drug Administration for the treatment of progressive, metastatic medullary thyroid cancer (MTC). In December 2013, the European Committee for Medicinal Products for Human Use (CHMP), issued a positive opinion on the Marketing Authorization Application (MAA), submitted to the European Medicines Agency, or EMA, for COMETRIQ for the proposed indication of progressive, unresectable, locally advanced, or metastatic MTC. Cabozantinib is being evaluated in a broad development program, including ongoing phase 3 pivotal trials in metastatic renal cell cancer (RCC), and advanced hepatocellular cancer (HCC).
Besides therapeutic efficacy, the Applicant continues to endeavor to provide suitable form(s) of Compound 1 that have favorable properties related to processing, manufacturing, storage stability, and/or usefulness as a drug. Accordingly, the discovery of new crystalline solid forms of Compound 1 that possesses some or all of these desired properties remains vital to drug development. Thus, disclosed herein are novel crystalline solid forms of Compound 1 that may be used in pharmaceutical compositions for the treatment of proliferative diseases such as cancer.